To solve the equation \( \frac{2}{15} - x = -\frac{3}{10} \), follow these steps:

1. **Isolate the variable \( x \)**:
\[
\frac{2}{15} - x = -\frac{3}{10}
\]
Add \( \frac{2}{15} \) to both sides to isolate \( x \):
\[
-x = -\frac{3}{10} - \frac{2}{15}
\]

2. **Find a common denominator** for the fractions on the right-hand side. The denominators are 10 and 15. The least common multiple (LCM) of 10 and 15 is 30.

3. **Convert the fractions** to have the common denominator of 30:
\[
-\frac{3}{10} = -\frac{3 \times 3}{10 \times 3} = -\frac{9}{30}
\]
\[
\frac{2}{15} = \frac{2 \times 2}{15 \times 2} = \frac{4}{30}
\]

4. **Combine the fractions**:
\[
-x = -\frac{9}{30} - \frac{4}{30} = -\frac{9 + 4}{30} = -\frac{13}{30}
\]

5. **Solve for \( x \)** by multiplying both sides by -1:
\[
x = \frac{13}{30}
\]

So, the solution to the equation \( \frac{2}{15} - x = -\frac{3}{10} \) is:
\[
x = \frac{13}{30}
\]